A method for calculating the pressure field about a ribbon parachutecanopy in steady descent

Muramoto, K. K.; Garrard, William L.

doi:10.2514/6.1984-794

Cited by 4 publications

(2 citation statements)

References 10 publications

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“…(2) in Eq. (5), one has (5) *'~~FS oq (6) ' Ik Equation (6) may be decomposed into two parts as where the terms containing the strength of the nascent vortices represent the velocity induced at the tip of the camber by the nascent vortices and (-u 0 + iv 0 ) 9 the velocity at the tip due to all other vortices (and their images), the doublet at the center of the circle in the f plane, and the ambient velocity. Equation (7) represents two coupled equations for the strengths and positions of the nascent vortices.…”

Section: (4) 47tmentioning

confidence: 97%

Numerical simulation of unsteady flow about cambered plates

Sarpkaya

Mostafa

Munz

1990

Journal of Aircraft

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Reported herein is a theoretical and experimental investigation of a nonimpulsively-started steady ambient flow, subsequently decelerating to rest at prescribed rates, about two-dimensional cambered plates (circular arcs with included angles of 120,180, and 240 deg) for the purpose of understanding the consequences of wake return and secondary separation on impermeable rigid surfaces. The numerical simulations are based on computational methods with vortices. Experiments are carried out in a vertical water tunnel. The results of the physical and numerical experiments are found to be in good agreement. NomenclatureA p = B 0 dU/dt/U*, or BS d"U/dt n /US +1 , acceleration parameters B 0 = opening width of cambered plate, = 2R sina = 4b B p = projected width of cambered plate b = B 0 /4 C d = drag coefficient, D/(2pbU%) c = radius of the circular cylinder D = drag force per unit length / = imaginary number Ksbr =B p /W t , solid blockage ratio q = velocity vector p = pressure R = radius of the camber R {} = real part of a complex quantity Re = Reynolds number, = B 0 U 0 /v r -radial distance T = U 0 t/c, normalized time T* = time at onset of deceleration t = time U = velocity U = d U/dt, acceleration U 0 = steady ambient velocity U s = velocity at separation point u =x component of velocity K! = tip velocity V 2 = velocity at the inner edge of the shear layer V t = tangential velocity component v -y component of velocity W t = tunnel width (24 in.) w = complex potential function z -x + iy, a point in the physical plane z n = location of the nth vortex z t = tip coordinate in the physical plane A* = time increment T n

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Section: (4) 47tmentioning

confidence: 97%

Numerical simulation of unsteady flow about cambered plates

Sarpkaya

Mostafa

Munz

1990

Journal of Aircraft

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“…The vortex sheet analysis was used by Klimas [3] to derive the acceleration-independent apparent mass coefficient for arbitrarily shaped axisymmetric surfaces. Muramoto and Garard [4] used a continuous-source model to predict the steady-state drag of ribbon parachutes. None of the analyses dealt with the evolution of the unsteady wake and its interaction with the canopy.…”

Section: Introductionmentioning

confidence: 99%

A Discrete-Vortex Analysis of Unsteady Flow About Cambered Plates

Mostafa

1989

International Conference on Aerospace Sciences and Aviation Tec

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The evolution of a two-dimensional, incompressible, rapidly decelerating, viscous flow about a sharp-edged camber is simulated through the use of discrete-vortex method. An extensive study of the velocity field in the vicinity of the singular points led to the development of a novel method for the introduction of vorticity. The roll-up of the vortex sheets, the distribution of velocity and the pressure on the camber, and the drag force are calculated and compared with experiments.

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Selection of Opening Model for Parachute Scaling Studies

Niemi¹

1992

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A method for calculating the pressure field about a ribbon parachutecanopy in steady descent

Cited by 4 publications

References 10 publications

Numerical simulation of unsteady flow about cambered plates

Numerical simulation of unsteady flow about cambered plates

A Discrete-Vortex Analysis of Unsteady Flow About Cambered Plates

Selection of Opening Model for Parachute Scaling Studies

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